摘要:

AbstractDuring recent developments on the theories and experimental techniques of compressed liquids and liquid mixtures, it has been revealed that there exist some regularities. Among these, the regularity found by Huang and O'Connell is that the isotherms of reduced bulk modulus of compressed liquids as a function of molar volume intersect at a common point. This intersection is a useful tool for evaluating the reliability of an equation of state (EOS) for producing equilibrium properties of matter. This paper also deals with an extension of the above regularity to some liquefied natural gas (LNG) mixtures including: N2+CH4, N2+C2H6, CH4+C2H6, CH4+C3H8, and CH4+C4H10at different temperatures. The present work gives a theoretical analysis for the common bulk modulus point in terms of a statistical‐mechanical equation of state for mixtures. In addition, we have calculated excess molar volume of N2+CH4mixture in terms of temperature and compared it with experimental value

ISSN:0009-4536    

DOI:10.1002/jccs.200500030

出版商:WILEY‐VCH Verlag    

年代:2005

数据来源: WILEY

摘要:

AbstractDensities, ρ, viscosities, η, and refractive indices, nD, of glycine (Gly) (0.1 — 0.5 M) in aqueous 1,2‐ethanediol (1,2‐EtD), 1,2‐propanediol (1,2‐PrD), and 1,3‐butanediol (1,3‐BuD) (30% v/v) were measured at 298, 303, 308, and 313 K. Experimental values of ρ and η were used to calculate partial molar volumes, ϕ0v, partial molar volumes of transfer of Gly from water to aqueous diol solutions, ϕ0v(tr), Falkenhagen and Jones ‐Dole coefficients, A and B, respectively, free energies of activation of viscous flow, Δμ0*1and Δμ0*2, per mole of solvent and solute, respectively, enthalpies, ΔH* and entropies, ΔS* of activation of viscous flow. Large positive values of ϕ0v, and an increasing value of Sv*, for all the three mixtures at each temperature suggest the presence of strong solute‐solvent interaction, and this interaction decreases as the size of alkyl moiety increases from 1,2‐EtD to 1,3‐BuD. Positive ϕ0v(tr) values tend to decrease with increasing the number of CH2group, thereby indicating that the electrostriction effect in diols follows the sequence; 1,2‐EtD>1,2‐PrD>1,3‐BuD. Small A values, with large values of B, are indicative of weak solute‐solute and strong solute‐solvent interactions that operate in the present systems, and that the magnitudes of B are in the sequence: 1,2‐EtD>1,2‐PrD>1,3‐BuD and, thus, the sequence represents the strength of interaction between Gly and diol molecules. Moreover, positive SB/ST values suggest the structure‐breaking nature of Gly in diol + water mixtures. The observed values of Δμ0*2fall in the sequence: 1,2‐EtD>1,2‐PrD>1,3‐BuD which, like ϕ0vand Sv*, reinforce that Gly‐diol interaction decreases with subsequent addition of CH2group in diols. The trends in the variation of ΔH* and ΔS* with Gly concentration also reveal the presence of significant solute‐solvent interaction in all three systems. An almost linear increase in RD with an increasing amount of Gly reveals that Gly tends to increase the polarizability of the aqueous‐diol molecules under study. The variation of all these parameters with concentration of Gly and with temperature suggests the presence of strong solute‐solvent interaction, which decrease

ISSN:0009-4536    

DOI:10.1002/jccs.200500031

出版商:WILEY‐VCH Verlag    

年代:2005

数据来源: WILEY

摘要:

AbstractSulfonate anion modified acrylic acid ter‐polymers and [2‐(methacryloyloxy)ethyl] trimethyl‐ammonium chloride cation modified acrylic acid polymers have been prepared and were characterized with small angle x‐ray diffraction studies. While the sulfonate anion modified acrylic acid ter‐polymer solutions exhibit strong scattering at an angle corresponding to a scattering vector 0.016 A−1, the cation modified acrylic acid polymers show no scattering at corresponding concentrations. The anion modified acrylic acid ter‐polymers are more compact than the corresponding cation‐modified acryli

ISSN:0009-4536    

DOI:10.1002/jccs.200500032

出版商:WILEY‐VCH Verlag    

年代:2005

数据来源: WILEY

摘要:

AbstractIn this paper the analytical equation of state (EoS) proposed by Ihm‐Song‐Mason was applied to calculate molar volume of mixtures of carbon dioxide with nitrogen and methane. The pair interaction potential has been used to evaluate the second virial coefficients and the ISM EoS parameters (i.e. α and b). The calculated values of the aforesaid quantities were applied to predict the molar volumes for mixtures of carbon dioxide with nitrogen and methane. Agreement with experiment was excellent for both mixt

ISSN:0009-4536    

DOI:10.1002/jccs.200500033

出版商:WILEY‐VCH Verlag    

年代:2005

数据来源: WILEY

摘要:

AbstractThe synthesis and characterization of some novel compounds of organotin(IV) chlorides with monomethyl glutarate is reported; the ligand molecule appears to be bound to the tin atom through the carbonyl oxygen. The results obtained through1H‐13C‐119Sn NMR, FT‐IR and119Sn Mössbauer spectra show that the diorganotin(IV) complexes have hexacoordination with octahedral geometry.Biological screening of the complexes reveals that the diorganotin(IV) complexes show significant activity against all microorg

ISSN:0009-4536    

DOI:10.1002/jccs.200500034

出版商:WILEY‐VCH Verlag    

年代:2005

数据来源: WILEY

摘要:

AbstractDepolymerization of an indigenous coal was studied in a variety of solvents at a temperature of 400 ± 10 °C in a hydrogen environment using a micro autoclave reactor for a time duration of 30 minutes. Some aliphatic, aromatic solvents as well as viscous petroleum based oils and pitches were used for evaluating them as liquefaction solvents. Amongst aliphatic solvents, 2‐propanol, and amongst aromatics, p‐creosol, gave highest yields. Petroleum pitches also proved effective, particularly their blends which caused significant depolymerization of the coal under study leading to formation of liquid pro

ISSN:0009-4536    

DOI:10.1002/jccs.200500035

出版商:WILEY‐VCH Verlag    

年代:2005

数据来源: WILEY

摘要:

AbstractThis study describes a turbidimetric technique for determination of melamine in wastewater of petrochemical companies. A single reagent (bioxalate ions) is used and an insoluble ion‐pair (melamine:bioxalate 1:3) produced. The reproducibility of the method is excellent and relative standard deviation for six repeated experiments is 1.5%. An interferences study was carried out, and it was found that the common species occurring in wastewater has no interference effect on the determination of melamine. The interference effect of Al3+was eliminated by its precipitation as Al(OH)3at pH 7. Finally this method was successfully used in the determination of melamine content of Urmia Petrochemical Company, a local melamine produce

ISSN:0009-4536    

DOI:10.1002/jccs.200500036

出版商:WILEY‐VCH Verlag    

年代:2005

数据来源: WILEY

摘要:

AbstractCationic and non‐ionic surfactant mediated systems have been studied as mobile phases in thin chromatographic studies of opium alkaloids on silica gel G. The effect of surfactant concentration below and above its critical micellar concentration on the mobility of alkaloids was examined. The influence of different alcohols (methanol, ethanol, propanol and butanol) in micellar solutions on the mobility and separation efficiency of alkaloids was assessed. The technique has also been applied for semiquantitative determination of codeine sulphate (2.5–35 μg) and papaverine. HCl (2.5–30 μg) in mixtures as well as in pharmaceuticals. The lower limits of detection of papaverine. HCl and codeine sulphate were 1.0 μg and 1.5 μg, res

ISSN:0009-4536    

DOI:10.1002/jccs.200500037

出版商:WILEY‐VCH Verlag    

年代:2005

数据来源: WILEY

摘要:

AbstractNew simple spectrophotometric and atomic absorption spectrometric (AAS) methods have been developed for the determination of levofloxacin (I), norfloxacin (II), and ciprofloxacin (III) in pure form, tablet formulations, and spiked human urine. The methods are based on the formation of ion‐pair associates between the drugs and the inorganic complex, bismuth (III) tetraiodide. The reaction occurs in acidic medium to form orange‐red ion‐pair associates which are instantaneously precipitated. The formed precipitates are then filtered off and the residual unreacted metal complex in the filtrate is determined either spectrophotometrically at 453 nm or by AAS at 223.1 nm. Also, the precipitates may be dissolved in acetone and quantified spectrophotometrically at 469 nm or decomposed by hydrochloric acid, and the bismuth content is determined by AAS at 223.1 nm. The methods permit the determination of the three studied drugs in the range of 5–80 μg mL−1. The proposed methods were successfully applied to determine these drugs in their tablet formulations and spiked urine samples without any evidence for interference from pharmaceutical additives or biological matrix. The results were in good agreement with those obtained by the reference methods. The proposed methods, especially if automated, can be confidently applied for quality control and routine analysis of the stu

ISSN:0009-4536    

DOI:10.1002/jccs.200500038

出版商:WILEY‐VCH Verlag    

年代:2005

数据来源: WILEY

摘要:

Abstract2,4‐Dichlorophenol (2,4‐DCP) and 2,4,6‐trichlorophenol (2,4,6‐TCP) by the use of cetylpyridinium chloride (CPCl) as a regulator was studied for their separation by the paper capillary permeation adsorption (PCPA) separation technique. The effect of pH, the type of PCPA treatment, the concentration of cetylpyridinium chloride, and various inorganic salts on the separatability has been investigated. A nearly 100% separatability was obtained at pH values 5–11 and 5–11, respectively, for 2,4‐dichlorophenol and 2,4,6‐trichlorophenol when cetylpyridinium chloride was present. It was confirmed that 2,4‐dichlorophenol and 2,4,6‐trichlorophenol are separated by adsorption on the fiber surface as ion pairs at the pH. Addition of inorganic salts decreases

ISSN:0009-4536    

DOI:10.1002/jccs.200500039

出版商:WILEY‐VCH Verlag    

年代:2005

数据来源: WILEY